Abstract

Trichotillomania (TTM) is a body focussed repetitive behaviour (BFRB) characterised by the repetitive pulling out of one’s hair. It is a moderately new disorder having only been classified in 1987 and it is under-researched relative to other psychological disorders. This thesis investigates TTM by presenting a series of experiments designed to further understand attitudes towards, and attentional biases in, TTM. The experiments in this thesis address 3 central issues: stigmatising attitudes towards TTM; attentional bias pertaining to the experience of shame in TTM; and attentional bias towards hair-related stimuli in TTM. Experiment 1 investigated differences in ratings of stigma towards perceived controllable (TTM, compulsive skin-picking) and perceived uncontrollable (alopecia, psoriasis) hair-loss and skin-lesioning conditions in a TTM and control group. The main findings indicated that stigma ratings varied as a function of group: the public rated perceived controllable conditions with higher stigma than perceived uncontrollable conditions while TTM participants rated these conditions equally. Experiment 2 used a modified emotional Stroop task using shame-related words to investigate the affective correlate of shame in individuals with TTM and a control group. TTMs did not demonstrate different response latencies to shame-related words, relative to other word types or the control group, indicating no evidence of attentional bias towards shame-related linguistic stimuli. Experiments 3, 4 and 5 focussed specifically on disorder-stimuli (i.e., hair-related) linguistic stimuli in a series of lexical paradigms. Experiment 3 was a lexical decision task and Experiment 4 was a modified Stroop task: these paradigms investigated response latencies towards hair-related words in TTMs and a control group. The main findings for both experiments showed that TTMs do not demonstrate an attentional bias towards hair-related words, relative to other word types and the control group. Experiment 5 investigated higher-level judgements of hair-related words in a word rating task. The findings revealed a group-by-word-type interaction for arousal ratings: TTMs rated hair-related words higher in arousal than body image and neutral words, and these ratings were higher than those of the control group for hair-related words. No group-by-word-type interaction for valence ratings was found. This indicates that TTMs rate hair-related words as more arousing but not more positive or negative, than other word types, relative to individuals without TTM. Finally, Experiment 6 utilised a modified dot probe paradigm to investigate attentional bias towards hair-related images. Our findings showed that TTMs disengage more slowly from hair-related images at a longer stimulus duration compared to neutral images, relative to control participants. This evidence is consistent with an attentional bias characterised by maintained attention towards hair-related stimuli in individuals with TTM. In conclusion, this thesis has presented evidence indicating that TTM (and other BFRBs) are associated with higher public stigma ratings than comparable perceived uncontrollable conditions. Results have also shown an attentional bias towards hair-related images but not words. This represents an important contribution towards the understanding of the processing of disorder-related stimuli in TTM. This may have implications for the maintenance mechanisms potentially involved in the hair-pulling condition.